Vulnerability-Lookup

rustsec-2022-0075

Vulnerability from osv_rustsec

Published

2022-11-10 12:00

Modified

2023-01-14 00:56

Summary

Bug in pooling instance allocator

Details

bug in Wasmtime's implementation of its pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance.

Mitigations are described here.

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "memory-exposure"
        ],
        "cvss": null,
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime",
        "purl": "pkg:cargo/wasmtime"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.0.0-0"
            },
            {
              "fixed": "1.0.2"
            },
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.0.2"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "CVE-2022-39393",
    "GHSA-wh6w-3828-g9qf"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "bug in Wasmtime\u0027s implementation of its pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance.\n\nMitigations are described [here](https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-wh6w-3828-g9qf).",
  "id": "RUSTSEC-2022-0075",
  "modified": "2023-01-14T00:56:30Z",
  "published": "2022-11-10T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/wasmtime"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2022-0075.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-wh6w-3828-g9qf"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/commit/2614f2e9d2d36805ead8a8da0fa0c6e0d9e428a0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/commit/3535acbf3be032ef1ba0b469b8ab92538a8a18a6"
    }
  ],
  "related": [],
  "severity": [],
  "summary": "Bug in pooling instance allocator"
}

CVE-2022-39393 (GCVE-0-2022-39393)

Vulnerability from cvelistv5 – Published: 2022-11-10 00:00 – Updated: 2025-05-02 12:51

Title

Wasmtime vulnerable to data leakage between instances in the pooling allocator

Summary

Wasmtime is a standalone runtime for WebAssembly. Prior to versions 2.0.2 and 1.0.2, there is a bug in Wasmtime's implementation of its pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance. This bug has been patched and users should upgrade to Wasmtime 2.0.2 and 1.0.2. Other mitigations include disabling the pooling allocator and disabling the `memory-init-cow`.

Severity ?

8.6 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

CWE

CWE-226 - Sensitive Information in Resource Not Removed Before Reuse

Assigner

GitHub_M

References

URL

Tags

	https://github.com/bytecodealliance/wasmtime/secu…	x_refsource_CONFIRM
	https://github.com/bytecodealliance/wasmtime/comm…	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	bytecodealliance	wasmtime	Affected: >= 2.0.0, < 2.0.2 Affected: < 1.0.2

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T12:07:42.224Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-wh6w-3828-g9qf"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/bytecodealliance/wasmtime/commit/2614f2e9d2d36805ead8a8da0fa0c6e0d9e428a0"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2022-39393",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-04-23T15:49:01.866453Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-04-23T16:39:11.212Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "wasmtime",
          "vendor": "bytecodealliance",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 2.0.0, \u003c 2.0.2"
            },
            {
              "status": "affected",
              "version": "\u003c 1.0.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Wasmtime is a standalone runtime for WebAssembly. Prior to versions 2.0.2 and 1.0.2, there is a bug in Wasmtime\u0027s implementation of its pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance. This bug has been patched and users should upgrade to Wasmtime 2.0.2 and 1.0.2. Other mitigations include disabling the pooling allocator and disabling the `memory-init-cow`."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 8.6,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-226",
              "description": "CWE-226: Sensitive Information in Resource Not Removed Before Reuse",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-02T12:51:28.525Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-wh6w-3828-g9qf",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-wh6w-3828-g9qf"
        },
        {
          "name": "https://github.com/bytecodealliance/wasmtime/commit/2614f2e9d2d36805ead8a8da0fa0c6e0d9e428a0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bytecodealliance/wasmtime/commit/2614f2e9d2d36805ead8a8da0fa0c6e0d9e428a0"
        }
      ],
      "source": {
        "advisory": "GHSA-wh6w-3828-g9qf",
        "discovery": "UNKNOWN"
      },
      "title": "Wasmtime vulnerable to data leakage between instances in the pooling allocator"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2022-39393",
    "datePublished": "2022-11-10T00:00:00.000Z",
    "dateReserved": "2022-09-02T00:00:00.000Z",
    "dateUpdated": "2025-05-02T12:51:28.525Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

GHSA-WH6W-3828-G9QF

Vulnerability from github – Published: 2022-11-10 21:16 – Updated: 2025-05-02 12:51

Summary

Wasmtime may have data leakage between instances in the pooling allocator

Details

Impact

There is a bug in Wasmtime's implementation of it's pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance. The pooling instance allocator in Wasmtime works by preallocating virtual memory for a fixed number of instances to reside in and then new instantiations pick a slot to use. Most conventional modules additionally have an initial copy-on-write "heap image" which is mapped in Wasmtime into the linear memory slot. When a heap slot is deallocated Wasmtime resets all of its contents back to the initial state but it does not unmap the image in case the next instance is an instantiation of the same module.

The bug in Wasmtime occurs when a slot in the pooling allocator previously was used for a module with a heap image, meaning that its current state of memory contains the initial heap contents of that module. If the next instantiation within that slot does not itself contain a heap image then Wasmtime would leave the old heap image in place erroneously and continue with instantiation. This means that instantiations of modules without a heap image can see the initial heap image of the prior instantiation within that slot.

Heap images in Wasmtime are created by precomputing WebAssembly data segments into one large mapping to be placed into linear memory at a particular offset. Most modules produced by toolchains today will have a heap image and an initialization snapshot. Creating a module without a heap image would require a hand-crafted *.wat file or a specially crafted source program. This consequence means that this bug is highly unlikely to be accidentally triggered and would otherwise require an intentional trigger with a hand-crafted module.

One important part of this vulnerability is Wasmtime is highly likely to segfault when the slot is reused again with a module that itself has an initialization image. For example if module A has a heap initialization image and module B does not have a heap initialization image, then the following sequence of events could happen if they all are instantiated into the same instance slot:

Module A is instantiated, and then deallocated. This leaves A's heap image in place, reset to its initial contents.
Module B is instantiated and erroneously can see the initial heap contents of A. Module B is then deallocated and the entire heap is unmapped and reset back to zero.
Module A is instantiated again, but the state tracking the slot did not account for module B so it thinks the module image is still mapped and proceeds with instantiation. Any action on A's part to access linear memory will then trap and if the host accesses A's memory it will segfault because the data that's supposed to be mapped is all unmapped.

Adding this all together this means that in practice modules must be deliberately crafted to not have an initial heap image to view the contents of a prior image. If this module is instantiated though then when the slot is reused the next, likely image-using, module will believe its memory is mapped when it isn't, causing the host to segfault on unmapped memory it believed was mapped.

Patches

This bug has been patched and users should upgrade to Wasmtime 2.0.2.

Workarounds

Trigging this bug requires the pooling allocator to be configured and for copy-on-write heap images to also be enabled. Pooling allocation is not enabled by default but copy-on-write heap images are. Mitigations for this bug include:

Disabling the pooling allocator - note that pooling allocation is not enabled by default in Wasmtime
Disabling the memory-init-cow feature or with Config::memory_init_cow

References

Config::allocation_strategy - configuration required to enable the pooling allocator.
Config::memory_init_cow - configuration required to enable or disable copy-on-write (this is enabled by default).
Mailing list announcement
Patch for release-2.0.0 branch
Patch for main

For more information

If you have any questions or comments about this advisory:

Reach out to us on the Bytecode Alliance Zulip chat
Open an issue in the bytecodealliance/wasmtime repository

Severity ?

8.6 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-39393"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-212",
      "CWE-226"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-11-10T21:16:22Z",
    "nvd_published_at": "2022-11-10T20:15:00Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nThere is a bug in Wasmtime\u0027s implementation of it\u0027s pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance. The pooling instance allocator in Wasmtime works by preallocating virtual memory for a fixed number of instances to reside in and then new instantiations pick a slot to use. Most conventional modules additionally have an initial copy-on-write \"heap image\" which is mapped in Wasmtime into the linear memory slot. When a heap slot is deallocated Wasmtime resets all of its contents back to the initial state but it does not unmap the image in case the next instance is an instantiation of the same module.\n\nThe bug in Wasmtime occurs when a slot in the pooling allocator previously was used for a module with a heap image, meaning that its current state of memory contains the initial heap contents of that module. If the next instantiation within that slot does not itself contain a heap image then Wasmtime would leave the old heap image in place erroneously and continue with instantiation. This means that instantiations of modules without a heap image can see the initial heap image of the prior instantiation within that slot.\n\nHeap images in Wasmtime are created by precomputing WebAssembly `data` segments into one large mapping to be placed into linear memory at a particular offset. Most modules produced by toolchains today will have a heap image and an initialization snapshot. Creating a module without a heap image would require a hand-crafted `*.wat` file or a specially crafted source program. This consequence means that this bug is highly unlikely to be accidentally triggered and would otherwise require an intentional trigger with a hand-crafted module.\n\nOne important part of this vulnerability is Wasmtime is highly likely to segfault when the slot is reused again with a module that itself has an initialization image. For example if module A has a heap initialization image and module B does not have a heap initialization image, then the following sequence of events could happen if they all are instantiated into the same instance slot:\n\n* Module A is instantiated, and then deallocated. This leaves A\u0027s heap image in place, reset to its initial contents.\n* Module B is instantiated and erroneously can see the initial heap contents of A. Module B is then deallocated and the entire heap is unmapped and reset back to zero.\n* Module A is instantiated again, but the state tracking the slot did not account for module B so it thinks the module image is still mapped and proceeds with instantiation. Any action on A\u0027s part to access linear memory will then trap and if the host accesses A\u0027s memory it will segfault because the data that\u0027s supposed to be mapped is all unmapped.\n\nAdding this all together this means that in practice modules must be deliberately crafted to not have an initial heap image to view the contents of a prior image. If this module is instantiated though then when the slot is reused the next, likely image-using, module will believe its memory is mapped when it isn\u0027t, causing the host to segfault on unmapped memory it believed was mapped. \n\n### Patches\n\nThis bug has been patched and users should upgrade to Wasmtime 2.0.2.\n\n### Workarounds\n\nTrigging this bug requires the pooling allocator to be configured and for copy-on-write heap images to also be enabled. Pooling allocation is not enabled by default but copy-on-write heap images are. Mitigations for this bug include:\n\n* Disabling the pooling allocator - note that pooling allocation is not enabled by default in Wasmtime\n* Disabling the `memory-init-cow` feature or with [`Config::memory_init_cow`](https://docs.rs/wasmtime/2.0.1/wasmtime/struct.Config.html#method.memory_init_cow)\n\n### References\n\n* [`Config::allocation_strategy`](https://docs.rs/wasmtime/2.0.1/wasmtime/struct.Config.html#method.allocation_strategy) - configuration required to enable the pooling allocator.\n* [`Config::memory_init_cow`](https://docs.rs/wasmtime/2.0.1/wasmtime/struct.Config.html#method.memory_init_cow) - configuration required to enable or disable copy-on-write (this is enabled by default).\n* [Mailing list announcement](https://groups.google.com/a/bytecodealliance.org/g/sec-announce/c/c1HBDDJwNPA)\n* [Patch for `release-2.0.0` branch](https://github.com/bytecodealliance/wasmtime/commit/2614f2e9d2d36805ead8a8da0fa0c6e0d9e428a0)\n* [Patch for `main`](https://github.com/bytecodealliance/wasmtime/commit/3535acbf3be032ef1ba0b469b8ab92538a8a18a6)\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\n* Reach out to us on [the Bytecode Alliance Zulip chat](https://bytecodealliance.zulipchat.com/#narrow/stream/217126-wasmtime)\n* Open an issue in [the bytecodealliance/wasmtime repository](https://github.com/bytecodealliance/wasmtime/)",
  "id": "GHSA-wh6w-3828-g9qf",
  "modified": "2025-05-02T12:51:03Z",
  "published": "2022-11-10T21:16:22Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-wh6w-3828-g9qf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-39393"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/commit/2614f2e9d2d36805ead8a8da0fa0c6e0d9e428a0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/commit/3535acbf3be032ef1ba0b469b8ab92538a8a18a6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/bytecodealliance/wasmtime"
    },
    {
      "type": "WEB",
      "url": "https://groups.google.com/a/bytecodealliance.org/g/sec-announce/c/c1HBDDJwNPA"
    },
    {
      "type": "WEB",
      "url": "https://rustsec.org/advisories/RUSTSEC-2022-0075.html"
    },
    {
      "type": "WEB",
      "url": "https://rustsec.org/advisories/RUSTSEC-2022-0098.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Wasmtime may have data leakage between instances in the pooling allocator"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

rustsec-2022-0075

Vulnerability from osv_rustsec

CVE-2022-39393 (GCVE-0-2022-39393)

GHSA-WH6W-3828-G9QF

Impact

Patches

Workarounds

References

For more information

Tags

Sightings

Nomenclature